Lawrence G. Keane, senior vice president and general counsel of The National Shooting Sports Foundation Inc., speaks in support of restrictions to prevent people with mental problems from obtaining weapons at a news conference at the Legislative Office Building in Hartford, Conn., on Monday.

HARTFORD, Conn. — Connecticut lawmakers Tuesday began reviewing mental health care following the deadly Newtown school shooting, even though they and the public have little insight into the mental state of the 20-year-old gunman.

The prosecutor in the case, Danbury State’s Attorney Stephen Sedensky III, said he cannot release information about Adam Lanza’s mental health because of the Connecticut Rules of Professional Conduct, which covers all attorneys in the state. His office is reviewing whether details of Lanza’s mental state can be released to the public after the police report is completed, possibly in June.

But Jeremy Richman, father of 6-year-old Arielle Richman, one of the 20 first-graders killed at Sandy Hook Elementary School on Dec. 14, told a legislative subcommittee on Tuesday that it is clear Lanza did not commit an impulsive act of violence, but rather a planned crime with the “goal of achieving infamy” like other mass shooters.

“The shooters in Sandy Hook, Tucson, Aurora, Littleton, Blacksburg — we will not grant them the respect of using their names — were not in their right minds,” said Richman, who, along with his wife, has started a foundation in their daughter’s name to protect vulnerable groups from violence and to understand the mental underpinnings of violent behavior.

“Too little is known in the mental health area about what drives these violent behaviors,” he said. “Clearly, something is wrong with the person capable of such atrocities.”

Besides gun violence and school safety, two task forces created by Gov. Dannel P. Malloy and the General Assembly are focusing on mental health services and reducing the stigma of treatment as they review public policy and recommend law changes after shooting, which also left six educators at Sandy Hook dead. Police said Lanza also killed his mother at the Newtown home they shared and later committed suicide as police approached the school.

The massacre in Newtown has also set off a national discussion about mental health care, with everyone from law enforcement leaders to the gun industry, urging policymakers to focus on the issue as a way to help prevent similar mass shootings.

Members of Malloy’s commission said they would like to have details of Lanza’s mental health, but it’s not essential.

“I don’t think not having that information is going to prevent us from doing important work,” said Dr. Harold Schwartz, a psychiatrist on the commission. “Adam Lanza is just one case. We really need to think about large populations. We need to think about improving the mental health system for everyone.”

Nelba Marquez-Greene, mother of 6-year-old Sandy Hook victim Ana Marquez-Greene and a licensed marriage and family therapist, said she hopes Connecticut will become a national model to improve its mental health system. In written testimony read by her sister on Tuesday, Marquez-Greene suggested that exposing families to trained mental health professionals to de-stigmatize mental health access and treatment. She also called for the state to fully fund programs that provide support to parents.

“My Ana Grace was murdered. She was six years old. She was one of 26 innocent people massacred senselessly,” Marquez-Greene wrote. “This tragedy could have been prevented.”

Lawmakers were urged to look at numerous issues such as stronger civil commitment laws, mandatory mental health evaluations for gun purchasers, more funding for school-based health centers that provide mental health care and community-based mental health services, and allowing families to put a troubled relative on a list preventing them from obtaining a gun. At the same time, some people diagnosed with mental illness told the legislators not to take out their anger with Lanza against them.

Slightly more than 100 people signed up to testify on Tuesday, compared to 1,200 who signed up to testify at Monday’s hearing on gun laws.

Jennifer Maxcell, a Newtown mother of three whose youngest son is a first grader at Sandy Hook, told the panel about how she worries for her mentally troubled 12-year-old son, who she said can be abusive toward her and his brothers. Maxcell said she’s been trying for years to get him services, but the shooting brought his problems to the forefront and prompted an emergency meeting with school officials.

“It took something like this. Because I don’t want another tragedy. Would I think he would do it? I don’t think so. But who knows? He’s 12 years old,” she said. “But if I don’t get him social skills to prepare himself for when he’s 18, what am I going to do?”

State lawmakers were told that individuals with private insurance have much more limited access to services than people using government insurance. Patricia Rehmer, commissioner of the Department of Mental Health and Addiction Services, said there are limits on the number of services that can be used annually, which can create problems for families.

“I am often called, especially by parents of young adults who are now keeping their children — young adults — on their insurance until they’re 26, who need the services that we provide,” Rehmer said of her agency, which serves only people without private insurance.

“They need case management. They need supportive housing. They need interactions with their peers,” she said. “Those are things that private insurance companies do not pay for.”